Nicolas Almagro came from behind to stun eight-time Barcelona Open champion Rafael Nadal in arguably the biggest upset in tournament history on Friday, winning in three sets to snap Nadal's 41-match winning streak in the Catalonian capital.

"There's still some work to do but I definitely took a step forward from yesterday. I move on feeling more assured. I needed this game," he said.

Picking up from where he left off on Thursday night, Nadal started fast on Friday, breaking Almagro in the first game of the opening set to pull ahead.

Surprisingly, Almagro would weather the storm, breaking right back and holding serve in the following game to take a 2-1 lead. As noted by Gilbert, the world No. 20's success was keyed by a series of aggressive shots and forehand winners:

Nico Almagro is ripping the ball any chance he gets so far vs Rafa + every time he hits winner making huge scream

Almagro's excitement would be short-lived, though, as Nadal rallied to win the final five games of the set, breaking twice in that span. Almagro's 15 unforced errors in the opening set were a big reason for his demise.

Almagro would rediscover his rhythm on serve in the second set, but Nadal kept the pressure on, forcing five break points through Almagro's first four service games.

Unfortunately for the world No. 1, he was unable to convert on any.

Manu Fernandez

The compatriots would hold serve through all 12 games of the second set, setting up a monumental tiebreak.

Despite falling behind 3-1 early in the extra session, Nadal would rally to win the next three points. However, determined to end his skid against the "King of Clay," it was all Almagro down the stretch as the 28-year-old won the final two points of the tiebreak to force a deciding set.

The third set featured even more drama and surprises, as Nadal watched a 3-1 lead turn into 4-3 advantage for Almagro midway through the set.

At this point, Almagro was booming with confidence, shouting words of encouragement to himself and playing ultra-aggressive and loose.

Lintao Zhang/Getty Images

Nadal would have his chances to break in the final game and extend the match, but Almagro proved too much in the end, capitalizing on Nadal's missed opportunities.

Rafa would conclude the match just 5-of-18 on break points and saw Almagro connect on clutch winner after clutch winner late in the match.

On Saturday, Almagro will be a favorite against either Giraldo or Kohlschreiber, considering he was able to hand Nadal his first loss at this event since he was just 15 years old. Plus, Almagro is coming off an appearance in the tournament final a year ago.

If Almagro can build on his performance Friday and continue to rip accurate forehands, there's an excellent chance he'll be competing for the crown on Sunday.

Manu Fernandez

With Rafa exiting the draw along with David Ferrer, who lost earlier this week, the sixth-seeded Almagro now appears poised to win his first ever Barcelona Open title this weekend.

Meanwhile, the loss is especially troubling for Nadal, as it marks his second defeat on clay in the span of a week. He was upset by Ferrer in the quarterfinals at Monte Carlo last week and now exits Barcelona at the same exact stage.

With the 2014 French Open just one month away, Nadal will need to quickly regain his confidence in order to retain the No. 1 ranking and continue his dominance on his preferred surface.